Mossbauer and Random anisotropy studies on amorphous ribbons

We have studied the Mossbauer and magnetization of melt spun amorphous Fe74-xAlxEr6B20 alloys with 0 less than or equal tox less than or equal to 15. Mossbauer studies were carried at room temperature as well as at 80 K. The average hyperfine field values are found to decrease with the Al concentration. Magnetization studies were carried out under magnetic fields up to 140 kOe. The results were analyzed using random magnetic anisotropy model. (C) 2001 Elsevier Science B.V. All rights reserved

Magnetic and Mossbauer studies of amorphous Fe72-xYxHo8B20 alloys

We have carried out magnetic and Mossbauer studies of amorphous Fe72-xYxHo8B20 alloys, The Fe moment decreases with the addition of Y and a magnetic compensation occurs at 4 K for x = 16, The temperature and field dependences of the magnetization have been interpreted using the mean field theory and Chudnovsky's model, respectively. These analyses yield some interesting parameters such as the random anisotropy, the exchange interactions J(Fe-Fe), J(Fe-Ho), etc. The Mossbauer studies show that the average hyperfine field decreases linearly with the addition of Y, in accordance with the decrease in the Fe moment

Functional Group Transformations in Derivatives of 6‑Oxoverdazyl

Transformations of functional groups, such as OCH₂Ph, OCOPh, NO₂ and I, in 1,3,5-triphenyl-6-oxoverdazyls <b>1a</b>–<b>1e</b> were investigated in order to expand the range of synthetic tools for incorporation of the verdazyl system into more complex molecular architectures and to increase spin delocalization. Thus, Pd-catalyzed debenzylation of the OCH₂Ph group or basic hydrolysis of the OCOPh group gave the phenol functionality, which was acylated, but could not be alkylated. Orthogonal deprotection of diphenol functionality was also demonstrated in radical <b>1c</b>. Pt-catalyzed reduction of the NO₂ group led to the aniline derivative, which was acylated. Attempted C–C coupling reactions to iodophenyl derivatives <b>1e</b> and <b>5e</b> were unsuccessful. Selected verdazyl radicals were characterized by EPR and electronic absorption spectroscopy, and results were analyzed with the aid of DFT computational methods

Combining Strong and Weak Gravitational Lensing in Abell 1689

We present a reconstruction of the mass distribution of galaxy cluster Abell 1689 at z = 0.18 using detected strong lensing features from deep HST/ACS observations and extensive ground based spectroscopy. Earlier analyses have reported up to 32 multiply imaged systems in this cluster, of which only 3 were spectroscopically confirmed. In this work, we present a parametric strong lensing mass reconstruction using 24 multiply imaged systems with newly determined spectroscopic redshifts, which is a major step forward in building a robust mass model. In turn, the new spectroscopic data allows a more secure identification of multiply imaged systems. The resultant mass model enables us to reliably predict the redshifts of additional multiply imaged systems for which no spectra are currently available, and to use the location of these systems to further constrain the mass model. In particular, we have detected 5 strong galaxy-galaxy lensing systems just outside the Einstein ring region, further constraining the mass profile. Our strong lensing mass model is consistent with that inferred from our large scale weak lensing analysis derived using CFH12k wide field images. Thanks to a new method for reliably selecting a well defined background lensed galaxy population, we resolve the discrepancy found between the strong and weak lensing mass models reported in earlier work. [ABRIDGED]Comment: ApJ in press, 668, 643. Final article with figures and online data available at http://archive.dark-cosmology.dk